A Small boy mischievously mixed small pebbles into a bag of pulses. What method will you employ to separate the mixture?
A.Magnetic separation
B.Crystallisation
C.Handpicking
D.Filtration

Hint:To get the solution one should have knowledge of metallurgy and extraction of metals .We can easily compare the size of pebbles and pulses because pebbles are larger in size and can easily be distinguishable ,this part is solved by using the purification part. That may include magnetic separation, crystallization, and filtration.

Complete step by step answer:
There are some terms first we have to understand them;
Ore is a mineral that contains enough metal to make it worth extracting the metal. Carbon also used to extract metal from some metal oxides. A metal can either be reduced or oxidized in a reaction. Once metal is extracted, metal undergoes further refining or purification. There are some basic methods which are used such as,
Handpicking: This is used when impurities are visible and that can easily be removed by hands.
Froth flotation: Gold and copper can be separated from crushed rock by a process known as froth floatation. Which uses detergent to create floating bubbles.
Magnetic separation: it is the process of separating components of mixture by using magnets to attract for magnetic separation detaches nonmagnetic material with those that are magnetic.
Crystallization: it is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.
Filtration: It is the process used to separate solids from liquids or gases using a filter medium that allow the fluid to pass through but not the solid .The term filtration applies whether the filter is mechanical, biological or physical.
For the above mentioned question, a boy mischievously mixed pebbles with pulses .Pebbles can be separated by using a handpicking method because the size of impurity that is pebbles are larger than pulses and that can be easily separated out.

Hence the correct option is C.

Note:
All ores are minerals not all minerals are ores. The least reactive metals such as gold, silver usually exist in native states.
They only need to undergo a physical separation process to be extracted.